1. Field of the Invention
The present invention relates to the field of telecommunications. More particularly, the present invention relates to routing of calls to a wireless network through an advanced intelligent network (AIN) network.
2. Acronyms
The written description contains acronyms that refer to various telecommunications services, components and techniques, as well as features relating to the present invention. Although some of these acronyms are known, use of these acronyms is not strictly standardized in the art. For purposes of the written description, the acronyms are defined as follows:
Advanced Intelligent Network (AIN)
Advanced Mobile Phone Service (AMPS)
Carrier Advanced Intelligent Network (CAIN)
Code Division Multiple Access (CDMA)
Direct Sequence Code Division Multiple Access (DS-CDMA)
Dual Tone Multi-Frequency (DTMF)
Electronic Key Telephone System (EKTS)
Global System for Mobile Communications (GSM)
Home Location Register (HLR)
Local Access and Transport Area (LATA)
Metropolitan Trading Area (MTA)
Mobile Identification Number (MIN)
Mobile Switching Center (MSC)
Mobile Telephone Switching Center (MTSC)
Personal Digital Assistant (PDA)
Personal Identification Number (PIN)
Plain Old Telephone Service (POTS)
Public Switched Telephone Network (PSTN)
Service Control Point (SCP)
Service Switching Point (SSP)
Signaling System 7 (SS7)
Signaling Transfer Point (STP)
Temporary Location Destination Number (TLDN)
Time Division Multiple Access (TDMA)
Trunk Group Trigger (TGT)
3. Background Information
Wireless devices, such as cellular telephones and personal digital assistants (PDA), have enabled mobile users to roam over large geographic areas while maintaining immediate access to telephony services. Wireless communication systems typically provide service to a geographic market area by dividing the area into many smaller areas called cells. Each cell is serviced by a base station, which receives and transmits on predetermined telecommunication radio frequencies, as directed by its associated controller. The cell sites connect to a mobile switching center (MSC), through land lines or other communication links. Each MSC is likewise connected to the public switched telephone network (PSTN), to enable communications between wireline and wireless parties.
The conventional method of connecting wireless and wireline networks is generally outlined below in reference to FIG. 1. An exemplary call is initiated at the calling party telephone 20 and routed from an originating end office switch, such as a service switching point (SSP) 21, to a tandem switch 24. A host MSC 31 receives the call from a tandem switch 24, deciphers the directory number and queries the home location register (HLR) 30, through a signaling transfer point (STP) 25, for example, to retrieve data indicating the current status of a mobile station 35. The data includes the identity of the MSC and/or trunk group at which the mobile station is currently registered based on the location of the mobile station 35. The HLR 30 is a database relating to mobile stations in the wireless network (e.g., based on the common NPA/NXX and/or carrier), including the mobile stations assigned to the MSC 31. When the MSC servicing the mobile station 35 is not the host MSC 31, such as servicing MSC 32, the MSC 31 routes the call to the servicing MSC 32 through a back haul facility. The servicing MSC 32 then completes the call to the mobile station 35 utilizing the appropriate wireless communications network elements, such as the base station servicing the cell in which the mobile station 35 is located, indicated by a base station 33.
The use of back haul facilities is inefficient and expensive. It increases routing and trunk group administration complexity, as well as traffic load on the MSCs. For example, in addition to handling calls to mobile stations currently located in its geographic area, the host MSC 31 must continue to handle all calls to each mobile station that it hosts (e.g., based on the corresponding NPA/NXX), regardless of where the mobile station is located. The present invention overcomes the problems associated with the prior art, as described below.